When It Burns
by Grey Silverstone
Summary: Season 7 Ep 1 slight spoilers  Cas is locked inside his head, and he's still fighting. Always. Because he has to.


_A/N: Post Season 7, Episode 1. It's what was going through my head when YOU KNOW WHAT happened. I suppose it's readable no matter what, but still! Sort-of-spoilers! Beware!_

_Disclaimer bit: Supernatural belongs to Supernatural. _

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><p>"How does it feel, Casti<em>el<em>?" Cas' face stares back at him, smile wide and manic. A million shadows push against the backs of his-eyes-that-aren't-his-eyes, not anymore. Cas is on ground unsolid, and the _pain_, the sheer _magnitude _of the pain is incredible. _It's in your head_. He tries to think the words, to give himself some show of strength.

He's failed.

Pain.

"Well, really, Cas— that's what they call you, isn't it?" Leviathan crouches down next to Cas on the ground, lit up red from behind. He cocks his head and strokes his hand through Cas' hair. "It's so nice, being here again. It's been too long." He yanks him up by the back of his head. Cas sputters, chokes, but he doesn't have time to cough, because he's already being thrown back down.

His head bounces on imagined asphalt, the _crack _his skull makes when it makes impact too loud in the empty space. He won't let the creature hear the groan that's shaking in his bones. _Pain_.

"Why are you doing this?" he chokes out, pushing up to his side. Leviathan continues walking around, looking up like he can see things that aren't there.

"Doing—oh. This?" Leviathan smiles again, raising his hand, fingers splayed open. And with the slightest flick of his wrist, Cas is yanked up by his spine and spun around, landing bodily against his hip.

"No," Cas growls after a moment, pushing back up. He won't let _it _win. Not with his face. "Why do you walk on Earth?"

"Because, Castiel." Leviathan walks over to Cas again, putting a hand against his jugular. Cas knows that, with a gesture, he will cease to exist. His mind will be gone, and this manifestation defeated. Cas stays very still.

Leviathan moves two fingers under Cas' chin and pulls up, up, lifting Cas to his feet.

Cas stumbles when the monster pulls away, gasping at the feel of bones realigning. His chin is damp; he raises his hand to it, and it comes away red.

"I _want _to walk," Leviathan says, beginning to walk again, hands clasped behind his back. It's a stroll in the park for the creature in his body, in his head. Cas fights back a surge of anger. What he needs is to be smart about this. Because, if Leviathan fights first, he will lose, and Leviathan will devour. "I want to walk, and I'm hungry. _Famished_, even. Have you ever felt real hunger, Cas?" Leviathan walks up to Cas and plants a hand, flat, against his abdomen, and everything in him shrivels in on itself, organs turning to other organs for sustenance, bones dissolving.

When he pulls away, Cas is bent double and gasping, shuddering as, once again, his body pieces itself back together.

"And there's a million things I can do, now," Leviathan continues. His smile grows as he continues to walk, until it looks as if it will fall off his face, scale off kilter with his dead, dark eyes. "I can _take _anything. Have anything I want, now. I can see what life is like on _Earth_," he spits, spite clear in every line of his—of Cas'—of _Jimmy's_—body.

And then black eyes go a shade darker, and the smile turns more subtle. "I could even take your _pets_—which one was your favorite? Dean. Dean Winchester." Leviathan walks until his nose is level with Cas' and presses against him, a laugh starting at the back of his throat. "I could take him, Cas. What do you think? I've seen inside your head. I could take. It. All."

Screw thinking smart.

Cas strikes out, catching Leviathan in the stomach and doubling him over in surprise. His knee follows, patella to sternum, and he pitches Leviathan over. It's natural, of course, to follow this by feet to ribs, by crouching down and taking his face by fists, _every. Single_. _Blow _for everyone he's failed, for everyone he's _promised_, for Sam and Bobby and _Dean_, and for losing this goddamn—

And then Leviathan is rolling out from under him, using his momentum against him. Cas jumps to his feet, and, suddenly, nothing hurts quite so much. But every sting in his knuckles from where skin split against teeth feels like heaven.

Leviathan shakes his head, blood-drenched smile macabre. "You can't win, Castiel. I'm stronger." Leviathan shoves him back and seizes his face between his hands, eyes intent on his. "I can do _anything _with you in here, Cas. You'll lose." And he presses his lips, bloody and vile, against Cas' own, brutal in his intensity.

And then it's a different mouth on his, warm and pliant and human. It's his hands on Cas' skin, and mouth on skin, and heat in all the right places. Cas closes his eyes, phantom kisses and finger tips making his back arch. His mouth opens against his skin, nails scrape over hyper sensitive skin. Fingers bury themselves in the roots of his wings, and Cas cries out, because it's every sensation he's wanted, and it's—

It's perfect.

Perfect. And when he pulls back for a moment too look at Dean, he melts away, and black eyes replace green ones, and Leviathan looms over him, smiling, blood gone. He's spotless. Cas blinks.

"That didn't do what you wanted it to."

"No? I'm pretty sure it—" And then he's silent and bloody again, because, Cas reasons, they are in _his _head, and so it's not too much of a stretch to figure out where the steering wheel behind him is coming from—from a million mind-clips of familiar hands resting against the plastic—and it's the easiest thing in the world to swing it around and catch Leviathan square in the mouth that _isn't his_, dammit.

And then, with a glare from the beast, he's somewhere else.

"Cas. _Cas_, Cas, wake up."

Cas comes to in an alley. The asphalt is black and slick with rain, and Dean is crouching over him, dragging his hands across Cas' face. It would be a beautiful moment if it didn't quite hurt so much.

Cas groans and tries to sit up; Dean pushes him back, eyes creased with concern and irritation. "No. Stay there for a second. What hurts?"

"Everything." Cas can't help the laugh that's probably inappropriate for this scenario. "Everything hurts. We're in my head."

"Cas…" Dean sighs, looping one of Cas's arms over his shoulder and pulling him to his feet. Cas is pressed against Dean's arm and, for the moment, it's good enough.

"God—you found him? Cas, are you…" Sam's concern, as always, is visible and vibrant, but there's not really anything he can say, so Cas waves him away. Bobby, at least, is silent, gun still raised. Not at Cas, but present. It's comforting.

"You guys go get the car," Dean says gruffly, tossing Sam the keys. Sam nods grimly, heading out of the alley, Bobby taking his back.

"Cas," Dean says quietly, and they're walking incredibly slowly. Cas is injured, not an invalid. He considers saying something, but he appreciates having Dean next to him, his hand clamped around his hip, hand held in his.

"Hm?"

"I… Who were you thinking about?"

"What do you mean, Dean?"

"I… dammit, Cas." Dean stops them, propping Cas up against the brick wall. Cas estimates about seven minutes before he begins sliding to the ground again, so he's hoping Dean can make this quick. "You were, um. Making noises—" And Dean's avoiding his eyes, so it's an embarrassing subject. Cas doesn't understand. There are plenty of noises one makes when one is in pain. Cas tells him so.

"Uh, no. _No. _Cas, I _know _pain noises. That wasn't—" Dean walks closer, and, in one smooth motion, pushes Cas flat and presses his hands into his hips, eyes angry and intent on Cas's. "Those. Weren't. _Pain_ noises."

"Maybe asks the others. I assume they heard it as well?"

"No, I… kept them away, a little. I didn't want to embarrass you."

"To embarrass—" Oh. "I see."

"Do you? I really don't think so," Dean says, rolling his eyes.

"Dean—why are we here? How did we get here? Do you remember?"

Dean frowns. "No. I was hoping you would."

Cas shakes his head. "No. I was… trapped. And I had visions of you, and then I was here."

It seems that Dean stops breathing for a moment. "Dreams?"

Cas realizes this should be awkward, and a secret, but there's not much point, he figures, if he's still stuck in his head, so he pushes forward and kisses him, gently enough to give him the hint.

Dean blinks at him. "Oh."

"This is all in my head," Cas explains. "So it doesn't matter what I do. But I have to get back, out of the hallucination, if I'm going to save any of you."

"Wait—how the hell did _I _end up in your head?"

Cas shrugs. "I don't know."

He thinks that neither knows what the other means, but he kisses back when Dean moves towards him again.

And then the sound of someone tutting down the alley.

"Tsk, tsk. What a dirty angel."

Dean jumps back like he's been burned, and spins back towards the mouth of the alley. "What the hell—Cas?"

"Ah—Cas is… He's gone." Leviathan grins at Dean, and, with a flick of his wrist, has Cas pinned up against the wall, body bending under the weight of his eyes. "There's a new sheriff in town."

And Dean is _Dean_. "And who's that? Officer Cliché? Asshole."

And Cas is pinned against the wall and Leviathan has a knife and Dean has a cut in his neck and he's _bleeding_, bleeding out all over the alley, and then it's Cas in his body, Cas holding the blade and looking down, smile frozen, at what used to be Dean, still so much left in his eyes, getting dark too fast, too soon.

"No," Cas tries to say, but he's trapped in his head, in his head, and he can't do a damn thing.

And then he's once more coming to on asphalt, and he's on his back, breathing like a fish, and Leviathan stands over him, looking happy and sated.

"Cas, Cas, Castiel." That smug bastard. "You can't win. You _can't_."

"No." Cas gets to his feet, and it's less shaky than last time. Because this time, his head gave him a weapon. "But you shouldn't have shown me that."

Leviathan grins. "And why's that?"

"Because _that _was my one good reason."

Nothing feels better than pulling the blade across Leviathan's neck and enjoying the shock he finds there. Shock and blood.

He waits for Leviathan to wake.


End file.
